DIY 5k Monitor - success :-)

[PaulD-UK]

@mmyk "...what is the general consensus for JRY SA1/FA1/AA1 board builds regarding cooling?"

If you put a 50 watt incandescent light bulb inside a sealed iMac case it will get quite hot after a while...
But, it won't be a problem as the aluminium case will dissipate this heat, so it won't rise to dangerous levels...

...for a light bulb, which is designed to run its filament at over 2000º...

The heatsink of the JRY--SA1 is designed to be fitted vertically against the back case ventilation slots above and below it.
This give adequate airflow over the heatsink fins.

In an iMac conversion, there is space for an internal airflow, but the air will heat up if it is trapped inside.
It doesn't seem to heat up too much so it kills the boards, because of the aluminium case, but it's anyone's guess if this actually shortens the life of the boards?

Allowing airflow over the rear of the board is definitely a good idea, and I'm doubtful if attaching a board directly against a 3D printed backing plate can be a good thing. 😱

Experience has shown that in practice the amount of airflow needed is actually very low, far less than the original iMac fan provides unless it is slowed right down.

I personally used the smaller fan from a 21.5" A1418 iMac, running at its slowest setting using a 4 wire PWM controller.
But most people don't seem to bother.....

 

[alexey-xxx]

@alexey-xxx
The JRY boards seem to work fine on 12V, the only thing that requires 24V is USB-C PD to power a laptop.

Strange behaviour of the Colour Mode. Does the 10 bit problem occur if you deactivate Better Display?
The other possible check to try to resolve this is to use a USB-C to DP 1.4 8K cable so you are using the DP input.
That usually gives the best performance with all these boards.
You could also try to power the board at 24V, to see if that improves 10 bit colour.

Monitor Control and Better Display are both controlling the display's audio volume in the same way at the same time.
I'm just using BD and it does both brightness and volume, very effectively.
But the volume setting on the Control Strip is also involved, so I keep that at the same setting so as to not have any effect.
Does disabling MC improve the audio, and give you volume control?

The amplifier chip used by JRY for the FA1 and SA1 boards probably has a high (up to ~10% THD) distortion at the levels needed in a monitor...

I tried a cheap amplifier board, but found the R1811 has (much) better sound.
I'm dubious of Chinese amplifier boards that are being sold at a price cheaper than Texas Instruments sell the audio amp chip that the amplifiers say they use....
The XH-A232 might work, I have no direct experience.

Yes, as soon as the 24V power supply arrives, I'll try it and report back. Switching off Better Display doesn't help. Through the DP 1.4 8K cable - goes default 8 bit and no such problems.

Monitor Control doesn't see the sound at all and doesn't adjust it in any way. When you press the volume keys - crossed out speaker.

Would it make sense to take a simple audio card and connect it via USB and connect the speakers to it? In this case the volume keys will work? I need the function of volume control from the keyboard.

 

[PaulD-UK]

The JRY—AA1 doesn’t have firmware that allows DDC keyboard volume control.
Maybe the SA1 is the same?

I don’t think anyone has reported fully on controlling the board’s audio, although someone else said it was ‘not good’.
A separate amp connected by USB should work fine.

@Ozpyn got audio volume control working with Windows, so that sounds like there should be some way to control it…

 

[alexey-xxx]

В JRY — AA1 нет прошивки, позволяющей регулировать громкость кнопок DDC.
Может быть, SA1 такой же?

Я не думаю, что кто-либо полностью отчитался о контроле звуковой платы, кто-то другой сказал, что он «не очень хорош».
Отдельный усилитель, подключенный через USB, должен работать нормально.

are there any examples of such audio cards with an amplifier? What kind of power should I look for? Or is a simple USB audio card and + XH-A232 enough?

Another question, if you connect the XH-A232 power supply to a common power supply, do you need to shield/isolate the power supply (I don't know the correct name).

 

[PaulD-UK]

USB input is usually done with a DAC that provides an analogue audio output to connect to the input of the main amp.

If the amp doesn’t have power supply input smoothing, then you may have to add a smoothing capacitor to get rid of noise from the PSU.

 

[DJLC]

If anyone has knowledge or experience in converting a 21.5" 4K iMac to an external monitor, or any pointers on the process in general from having done it or heard people who have, that would be SUPER appreciated 🙏.

It's been a couple years since I built my two 21.5" 4k iMac displays. LOVE them. Back when I ordered my boards, I learned the hard way that you definitely should crack the iMac open to check the specific panel revision. My first board was for SDA1, but my first iMac ended up having an SDB1 panel. Luckily, I was able to bridge a contact on the board to make it work. When I built the second one, I made sure to check first + order the correct board.

Not sure about the newer board. If it says it supports all those revisions, it's probably worth a shot. But if you get an older / cheaper board, definitely do check the panel first.

No major tips otherwise... I pulled the original power socket out of the iMac chassis so I had a hole to pass cables through. Stuck the control board ribbon out the Ethernet port + used double sided tape to position the control board over the empty port holes. Wired the speakers up to the board directly; doesn't sound amazing, but good enough as I mostly use separate external speakers. External power supplies + DisplayPort + Lunar for brightness control, good to go. The only thing I'd do differently is wire the original power button up.

 

[ItsAShaunParty]

So I'm about to purchase a $277 r1811 board... I wasn;t thrilled about it. It was this one. When I scroll down and the description says:

... And they're right! It's only $85.32!

I guess we don't know the audio quality. And we don't know what the firmware's like.

I guess I'll get the expensive one. Unless someone can talk me out of it...

 

[PaulD-UK]

@ItsAShaunParty The cheap one they are so desperate to offload is the JRY-W9CUHD-AA1.
Lots of previous posts about it earlier in this thread.
Spoiler: It works (8 bit), it has some problems - 30Hz HDMI, no DDC etc etc.

On my screen the R1811 from AliExpress has VAT added.
I got on better buying straight from the vendor, who communicates in English and understands the product...

 

[ItsAShaunParty]

@ItsAShaunParty The cheap one they are so desperate to offload is the JRY-W9CUHD-AA1.
Lots of previous posts about it earlier in this thread.
Spoiler: It works (8 bit), it has some problems - 30Hz HDMI, no DDC etc etc.

On my screen the R1811 from AliExpress has VAT added.
I got on better buying straight from the vendor, who communicates in English and understands the product...

I have $292 including shiping from Aliexpress. Same from the seller you recommend.

What's the cheapest board that you find reliable for 5k?

But you're confident with the R1811. I can get 5k, decent audio, and maybe even rig up the original power button? I'll just bite the bullet....

 

[alexey-xxx]

Yes, as soon as the 24V power supply arrives, I'll try it and report back. Switching off Better Display doesn't help. Through the DP 1.4 8K cable - goes default 8 bit and no such problems.

Connecting to a 24V supply had no effect.
When connected via USB-C, there is no 10-bit Full Range mode available. Why? USB4.0, 8K60Hz cable - maybe bad? When connected via DP1.4, 10-bit Full Range mode is available and gives a good picture. With Limited Range mode - the image on the display is backlit.

 

[ItsAShaunParty]

@ItsAShaunParty The cheap one they are so desperate to offload is the JRY-W9CUHD-AA1.
Lots of previous posts about it earlier in this thread.
Spoiler: It works (8 bit), it has some problems - 30Hz HDMI, no DDC etc etc.

On my screen the R1811 from AliExpress has VAT added.
I got on better buying straight from the vendor, who communicates in English and understands the product...

I completely forget. Why did we decide against the R9A18? Is it challenging to get 5k on it?

 

[PaulD-UK]

@ItsAShaunParty "I completely forget. Why did we decide against the R9A18? Is it challenging to get 5k on it?"

Basically the same company produced the R9A18 (V1 and V1.1) then decided to make a redesigned, better, product, the R1811 (V3 prototype, and V4 production version).

So the R9A18 was good board to be driven by 2017-2019 Macs, which only had DP 1.2 capability.
Using two DP 1.2 cables between the Mac and the R9A18 was the only way to get 5K/60 before DP 1.4 was introduced in 2019.

With DP 1.4 a single cable using DSC (display stream compression) could do 5K/60 10 bit.
The R1811 was the board introduced to do this, and since it's introduction it had received half a dozen firmware updates to get the best performance possible, and show the best information.

So to use a R9A18 with a modern Mac, you can either run two DP cables from the Mac, or use a Thunderbolt 3 to two DP adapter to get one TB3 cable to split into 2xDP 1.2.
Then you need two DP cables to run to the R9A18 inputs.
If you use a single DP 1.4 cable the R9A18 only runs 5K/60 at 8 bit Limited Range 4.2.2.

So as well as the R9A18 you have to buy a TB3 cable, two DP cables and the TB3 to 2xDP adapter.
The cost of that brings the total cost of the board up by quite a bit.

In effect the R1811 costs about £50-£70 more than the R9A18 (+ adapter and cables), but the R1811 is a board that is still being produced (and the firmware developed), whereas the R9A18 is no longer in production and most probably old stock.

That being said, @Kaeslin has built a really nice R9A18 conversion.
The OWC TB3 to dual DP adapter he used cost between £70 (Flexx) to £99 (Amazon).

 

[alxdrsyrbu]

Hey guys!
Appreciate all the info from this thread, I'm currently planing to order all the stuff I'll need for the conversion and just wanted to make sure about the cable situation.

So I'm deciding on a cable set for JRY-W9RQUHD-FA1 and I like the idea of buying one short DP 1.4 (inside the iMac) to HDMI 2.1 (hanging on the outside) adapter and then plugging 8k HDMI cable into that adapter. This will allow me to use this display with both xbox (hdmi) and MBP (hdmi to type-c adapter).

The only reason for me to take DP 1.4 to HDMI 2.1 adapter here is because as I understood so far, DP sometimes gives a better result without any issues on FA1. Am I right or they're equally good on FA1 board?

What do you think overall about this and maybe you got any better idea without 2 full cables (hdmi to hdmi & hdmi to type-c) hanging from the display?

 

[PaulD-UK]

@alxdrsyrbu "The only reason for me to take DP 1.4 to HDMI 2.1 adapter here is because as I understood so far, DP sometimes gives a better result without any issues on FA1. Am I right or they're equally good on FA1 board?"

No one reporting in this thread has done a proper test of the results of the HDMI input compared to the DP inputs, on either the JRY--FA1 or JRY--SA1.

No one has really used a DP to HDMI adapter, so the results of that aren't really known.

If you do go ahead and with your plans, and the results aren't good enough, then the simple solution is to use a USB-C to DP 1.4 8K cable from the Mac, and a HDMI 2.1 cable for the X-Box.

By the way, cables are described in the direction of the video signal flow:
From the Mac's USB-C output port to the DP input port you use a 'USB-C to DP' cable.

This is important as cables only work both ways if they are 'bidirectional', and most cables aren't, and only work one way.

If you call it 'hdmi to type-c' then the cable will only work on a JRY--SA1 board, feeding the signal from the Mac's HDMI port to the board's USB-C input port.

 

[alxdrsyrbu]

@PaulD-UK got it! Appreciate you response, you're a true legend of this thread!

 

[Bacon&Cabbage]

Long time lurker here. First off, thanks to everyone here for their questions and answers - @PaulD-UK deserving of special mention for his knowledge and patience.
I'm just reporting a successful conversion of a Late 2015 5K iMac using the JRY-W9CUHD-AA1 board (99 euro on AliExpress). The 24V 6A power adapter I bought from amazon.es (15 eur) was claimed to be 30mm thick but turns out to be 36mm so unfortunately it has to stay outside of the iMac until I can get an ADT-120A24AA or equally thin power adapter.
I downloaded these brackets (use the latest available STL files) and got them 3D-printed using xometry (7 eur), put in some M3 brass inserts (1 eur, AliExpress) using a soldering iron (3 eur) and now the driver board is secure and sits just above the RAM door for easy access to all the ports. I connected the iMac's power button to the JRY's button board so it powers on the display too.
I did some experiments with speakers but dropped them, I use external speakers all the time anyway.
For connections I bought a bunch of USB4 cables and HDMI extenders/DisplayPort extenders from Ali but all I will probably be using is the USB connection to my Mac Mini M4 and every so often the wife's M3 MacBook. I also bought a joystick (haven't connected it yet) and a couple of female-female USB4 dongles. The dongles work fine and more importantly the smaller female end can be squeezed through the USB3 socket holes in the iMac's case so once I sort out a thinner power adapter and some 90-degree angle USB4 connectors, I will hopefully be able to have a stock iMac experience with original power cable, the joystick control out the Ethernet port, and a USB4 connection through one of the 4 USB3 holes. The RAM access cover can be removed for access to the DisplayPort and HDMI ports should they be needed.

 

[mmyk]

@alxdrsyrbu "The only reason for me to take DP 1.4 to HDMI 2.1 adapter here is because as I understood so far, DP sometimes gives a better result without any issues on FA1. Am I right or they're equally good on FA1 board?"

No one reporting in this thread has done a proper test of the results of the HDMI input compared to the DP inputs, on either the JRY--FA1 or JRY--SA1.

No one has really used a DP to HDMI adapter, so the results of that aren't really known.

If you do go ahead and with your plans, and the results aren't good enough, then the simple solution is to use a USB-C to DP 1.4 8K cable from the Mac, and a HDMI 2.1 cable for the X-Box.

By the way, cables are described in the direction of the video signal flow:
From the Mac's USB-C output port to the DP input port you use a 'USB-C to DP' cable.

This is important as cables only work both ways if they are 'bidirectional', and most cables aren't, and only work one way.

If you call it 'hdmi to type-c' then the cable will only work on a JRY--SA1 board, feeding the signal from the Mac's HDMI port to the board's USB-C input port.

Hi, I happen to have the FA1 board. I have bought a 1 meter "8k HDMI" cable from Ugreen which to my knowledge is a decent brand. The results were not good. I have tried the following setups, all via said HDMI cable:

1. Connected directly to Dell Precision 5680: maxed out at 4k.
2. Connected to Dell Precision 5680 via Dell WD19TB docking station: maxed out at 4k.
3. Connected to base MacBook Air M2 via Dell WD19TB docking station: got some ridiculous resolution, e.g. 1280x720 or similar.

I then bought a DP1.4 cable. In all 3 cases above I am getting 5k output through both DP ports on the FA1 board. I have not checked on bit depth though. In the end I am not sure whether it was a faulty/incompatible HDMI cable or FA1 board is not up to task via HDMI. The board has been purchased directly from StoneTaskin. I did not further investigate as DP has always been my preferred AV connection which I am going to stick to.

 

[J@ffa]

@PaulD-UK Hi there, sorry to be a pest as you've given a lot of time to this thread already! I'm looking to convert an 27" 2015 iMac and am planning to get an R1811 and any other bits I need or that are recommended.

Can I ask if there's a rundown anywhere oriented at the UK, and where you'd recommend ordering the main bits from? Thank you! I've looked at a few of the sellers (Stonetaskin's website, and some Aliexpress listings) but can't figure out where's best.

 

[PaulD-UK]

@mmyk The problem with your JRY--FA1 board and it's HDMI input is that although your cable is HDMI 2.1, both your Dell laptop and the Dell dock are only HDMI 2.0 (or 2.0a or 2.0b, which is for 4K HDR or 120+Hz monitors).

So neither can do better than 4K/60, and the MBA can only do 4K through the Dell dock's HDMI port, but as it's a Mac that is likely to be 1080p HiDPI as the default.

Stick with DP for input with those computers.
It needs a M2/3/4 Pro/Max or later Mac to have HDMI 2.1

 

[PaulD-UK]

@J@ffa StoneTaskin's delivery service to the UK is a good deal better than AliE in my experience, and they can deal with you in English...
As to all the other bits, there is no central UK source to get things from.
It comes down to googling and choosing from the results as to where best to order things from.

 

[J@ffa]

@J@ffa StoneTaskin's delivery service to the UK is a good deal better than AliE in my experience, and they can deal with you in English...
As to all the other bits, there is no central UK source to get things from.
It comes down to googling and choosing from the results as to where best to order things from.

That's great advice, thank you. Do you know if it's worth getting the speaker board that you and others have mentioned in this thread? Wondering how close it is to the normal performance of the iMac's speakers.

 

[PaulD-UK]

@J@ffa
The R1811 can sound quite good when connected to the speakers with a two-way crossover.

The bigger red YLY-2088 speaker crossover kit is not the best choice, as it's really designed for an 8 ohm car audio system. It has good soldering-free cables.

The smaller Balee 2.1 kit looks much better, and has a proper air-cored inductor of about the right size, but it looks like has a cheap electrolytic capacitor, which aren't as good as a proper audio polypropylene capacitor.

The circuit for the crossover is really simple.
C1 is a 10 microFarad audio capacitor, and L1 is a 0.15 milliHenry air-cored inductor:

 

[ItsAShaunParty]

@ItsAShaunParty "I completely forget. Why did we decide against the R9A18? Is it challenging to get 5k on it?"

Basically the same company produced the R9A18 (V1 and V1.1) then decided to make a redesigned, better, product, the R1811 (V3 prototype, and V4 production version).

So the R9A18 was good board to be driven by 2017-2019 Macs, which only had DP 1.2 capability.
Using two DP 1.2 cables between the Mac and the R9A18 was the only way to get 5K/60 before DP 1.4 was introduced in 2019.

With DP 1.4 a single cable using DSC (display stream compression) could do 5K/60 10 bit.
The R1811 was the board introduced to do this, and since it's introduction it had received half a dozen firmware updates to get the best performance possible, and show the best information.

So to use a R9A18 with a modern Mac, you can either run two DP cables from the Mac, or use a Thunderbolt 3 to two DP adapter to get one TB3 cable to split into 2xDP 1.2.
Then you need two DP cables to run to the R9A18 inputs.
If you use a single DP 1.4 cable the R9A18 only runs 5K/60 at 8 bit Limited Range 4.2.2.

So as well as the R9A18 you have to buy a TB3 cable, two DP cables and the TB3 to 2xDP adapter.
The cost of that brings the total cost of the board up by quite a bit.

In effect the R1811 costs about £50-£70 more than the R9A18 (+ adapter and cables), but the R1811 is a board that is still being produced (and the firmware developed), whereas the R9A18 is no longer in production and most probably old stock.

That being said, @Kaeslin has built a really nice R9A18 conversion.

Hey,

I spent a lot of time writing a really complimentary note, but then my browser closed, and it disappeared! I thought drafts were saved automatically on this site, but it wasn't there. But you can imagine. Thanks for being so helpful!

Anyway, I was saying you should create a simple website—maybe a blog—to compile all your knowledge on this. It would be a fantastic resource! For example, I've done simple upgrades before, like installing an SSD in a 21.5" iMac, but this project is a step up for me. It'll be my first time using a multimeter, and I’m excited, but I wish I had detailed, definitive directions (preferably a video). Like, I'm not 100% sure how to use the multimeter...

Okay, final stuff....
I'm planning to use the R1811. Ideally, I’d like to repurpose the iMac’s original power button and plug, if possible. Also, instead of mounting physical switches, I'd love to use a remote control—does this board support that? I also plan to keep the original speakers mounted and try to get those working.

I forgot to ask about the microphone—if possible, I’d like to keep that, too. Is it straightforward to integrate?

I'm also working with a 21.5" LM215WF3 (SD)(DS) panel I'm converting. Nothing special. Just the monitor.

Questions....​

1. R1811 Kit– I’d like to get a kit that includes most of what I need. Do either of these options cover it? If not, do you know where I can find a more complete kit?
   • Option 1
   • Option 2
2. Microphone?
3. Crossovers – You recommended these
4. For the 21.5" Display – This board. Any key things to watch out for or additional parts I’ll need?

Would love your input—thanks in advance!

 

[PaulD-UK]

@ItsAShaunParty
"I’d like to repurpose the iMac’s original power button and plug..."

To use the iMac's original power button, you wire the cable from the button in parallel to the Control Strip power-on switch K1, pins 3 and 4 (from L) Gnd and Power on the ribbon cable. The plug isn't really usable, as the wire needs to be extended, and soldering is easier.

"I'd love to use a remote control..."
Yes, StoneTaskin sell the remote control that works with the R1811.
This pic shows the same remote control that works with the R1811, R9A18 and the R9513 V5 board for 4K 21.5" iMacs.
The IR receiver is on the Control Strip next to the ribbon cable, so this needs to be able to receive the signal from the remote.
On my conversion I find it works fine inside the back of the case, so the Strip can be hidden away.
I put a dark plastic window that passes the IR signals through to the inside.

Apple fits iMacs with multiple internal microphones which are mixed through a Digital Signal Processor to get good noise reduction and clear output.

This is more or less impossible to recreate in a DIY build, though people have added a single microphone, like @Aiwi did in his blog.
Generally the results are mixed. Every YouTuber uses an external close range microphone, because that is the only way to get good sound...
An iPhone using Continuity Camera for a webcam also does sound with Apple's magic touch. 🫨

 

[alxdrsyrbu]

@PaulD-UK hey, talking about power button, I've seen 2 other guys solder original cables straight to the control strip's power button pins. Is it also a good idea or is there any difference?

22:00

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